Patent application title: ASSEMBLY OF BICYCLE COMPONENTS IN MUTUAL ROTATION AND BICYCLE COMPRISING SUCH AN ASSEMBLY

Abstract:

The invention relates to an assembly (1) of bicycle components in mutual
rotation, like for example a bottom bracket assembly. The assembly of the
present invention comprises a support element (15), a rotary element (5)
rotatably coupled with the support element (15) and at least one bearing
(20) arranged between the support element (15) and the rotary element
(5). The bearing (20) comprises at least one bearing element (30, 40)
firmly coupled with one from the support element (15) and the rotary
element (5). The bearing element (30, 40) and the element (5, 15) with
which it is firmly associated have, at respective mutually coupled
interface surfaces (36, 38, 42, 44),a standard reduction potential
difference lower than or equal to 0.3 V, in absolute value.

Claims:

1. An assembly (1, 201, 301) of bicycle components in mutual rotation,
comprising a support element (15, 205, 315), a rotary element (5, 215,
305) rotatably coupled with the support element (15, 205, 315), at least
one bearing (20, 220, 320) arranged between the support element (15, 205,
315) and the rotary element (5, 215, 305), the at least one bearing (20,
220, 320) comprising a first bearing element (30, 240, 340, 40, 230, 330)
firmly coupled with one of the support element (15) or the rotary element
(5), wherein the first bearing element (30, 240, 340, 40, 230, 330) and
the one of the support element (15, 205, 315) or the rotary element (5,
215, 305) have, at respective mutually coupled interface surfaces (36,
38, 42, 44), a standard reduction potential difference less than or equal
to 0.3 V, in absolute value.

2. The assembly (1, 201, 301) of claim 1, wherein the standard reduction
potential difference is less than or equal to 0.2 V, absolute value.

4. The assembly (1, 201, 301) of claim 3, wherein at least one of the
first bearing element (30, 240, 340) and the one (5, 215, 315) of the
support element (15, 205, 315) or the rotary element (5, 215, 305) has,
at the respective interface surface (36, 38), a standard reduction
potential comprised between 0.16 and 0.18 V, extremes being included.

5. The assembly (1, 201, 301) of claim 1, wherein the interface surface
(36) of the first bearing element (30, 240, 340) is made from stainless
steel.

6. The assembly (1, 201, 301) of claim 1, wherein the interface surface
(38) of the one (5, 215, 305) of the support element (15, 205, 315) or
the rotary element (5, 215, 305) is made from a material selected from
the group consisting of: stainless steel, aluminum alloy treated with
anodic oxidation, metallic material coated with chemical nickel, and
composite material having a filler incorporated in a matrix of polymeric
material, wherein the filler is coated with an insulating surface layer.

8. The assembly (1, 201, 301) of claim 7, wherein the second bearing
element (40, 230, 330) and the support element (15, 205, 315) comprise
respective mutually coupled interface surfaces (42, 44), at which there
is a standard reduction potential difference less than or equal to 0.3 V,
absolute value.

9. The assembly (1, 201, 301) of claim 8, wherein at least one of the
second bearing element (40, 230, 330) and the support element (15, 205,
315) has, at the respective interface surface (42, 44), a standard
reduction potential between 0.16 and 0.18 V, extremes being included.

10. The assembly (1, 201, 301) of claim 7, wherein the second bearing
element and the support element comprise respective mutually coupled
interface surfaces and wherein the interface surface (42) of the second
bearing element (40, 230, 330) is made from stainless steel.

11. The assembly (1, 201, 301) of claim 7, wherein the second bearing
element and the support element comprise respective mutually coupled
interface surfaces and wherein the interface surface (44) of the support
element (15, 205, 315) is made from a material selected from the group
consisting of: stainless steel, aluminum alloy treated with anodic
oxidation, metallic material coated with chemical nickel, composite
material having a filler incorporated in a matrix of polymeric material,
wherein the filler is coated with an insulating surface layer.

12. The assembly (1, 201, 301) of claim 7, wherein the first (30, 240,
340) and second (40, 230, 330) bearing elements comprise respective
rings, and the bearing (20, 320, 320) also comprising a plurality of
rolling elements arranged between the rings.

13. The assembly (1, 201, 301) of claim 12, wherein the rolling elements
are made from ceramic material.

14. The assembly (1, 201, 301) of claim 13, wherein the ceramic material
has a density less than or equal to that of steel.

15. The assembly (1, 201, 301) of claims 12, wherein no lubricants are
provided in the bearing (20, 220, 320).

16. The assembly (1, 201, 301) of claim 1, wherein the assembly is an
assembly selected from the group consisting of: a bottom bracket assembly
(1), a hub assembly (201), or a steering assembly (301).

17. Bicycle comprising at least one assembly of bicycle components in
mutual rotation, comprising a support element (15, 205, 315), a rotary
element (5, 215, 305) rotatably coupled with the support element (15,
205, 315), at least one bearing (20, 220, 320) arranged between the
support element (15, 205, 315) and the rotary element (5, 215, 305), the
at least one bearing (20, 220, 320) comprising a first bearing element
(30, 240, 340, 40, 230, 330) firmly coupled with one of the support
element (15) or the rotary element (5), wherein the first bearing element
(30, 240, 340, 40, 230, 330) and the one of the support element (15, 205,
315) or the rotary element (5, 215, 305) have, at respective mutually
coupled interface surfaces (36, 38, 42, 44), a standard reduction
potential difference less than or equal to 0.3 V, in absolute value.

18. A coupling between members of a bicycle assembly (1, 201, 301),
comprising:a fixed member (15, 205, 315);a rotational member (5, 215,
305) coupled to the fixed member through the interposition of at least
one bearing (20, 220, 320);wherein, at least one bearing surface (36) is
firmly coupled to at least one member surface (38) of at least one of the
fixed member or the rotational member, and the at least one bearing
surface and the at least one member surface have a maximum standard
reduction potential difference of 0.3 V.

19. The coupling of claim 18 comprising first and second bearing surfaces
(36) firmly coupled to first and second member surfaces (38) of each of
the fixed member (15, 205, 315) and the rotational member (5, 215, 305).

20. The coupling of claim 18 wherein the fixed member (15, 205, 315) is
positioned radially inward with respect to the rotational member (5, 215,
305).

Description:

FIELD OF INVENTION

[0001]The present invention relates to an assembly of bicycle components
in mutual rotation.

BACKGROUND

[0002]Throughout the present description and in the subsequent claims, the
expression "assembly of bicycle components in mutual rotation", is used
to indicate any bicycle assembly defined at two bicycle components
assembled together so that, during pedalling, they can rotate with
respect to one another. Such an assembly therefore comprises at least one
support element, at least one rotary element supported in rotation by the
support element and at least one member arranged between the support
element and the rotary element to allow the relative rotation of one
element with respect to the other element. Examples of such an assembly
are a bottom bracket assembly, a hub assembly or a steering assembly.

[0003]The invention also relates to a bicycle comprising the
aforementioned assembly. Preferably, such a bicycle is a racing bicycle.

[0004]In the field of bicycles, above all in racing bicycles, the problem
of the smoothness capability of those components that, during pedalling,
are in mutual rotation has always been researched. This has been done as
part of the continuing search to improve the bicycle performance.

[0005]Typically, the rotation of one component with respect to another in
bottom bracket assemblies, or in hubs or in steering tubes, of bicycles
is achieved through the use of rolling bearings.

[0006]In the past it has been observed that the initial smoothness
capability of bicycle components assembled together and in relative
rotation decreased over time, until it substantially reduces after a
certain time; this phenomenon was due essentially to the accumulation on
the bearings of atmospheric and/or polluting agents.

[0007]In order to limit this phenomenon, in racing bicycles nowadays ball
bearings are used to which insulating grease is applied; indeed, the
grease hinders the formation of corrosion. In order to hold the grease
and therefore protect the inside of the bearings from the undesired
action of atmospheric and/or polluting agents, special protective screens
are used.

[0008]Despite the aforementioned provisions, a decrease in the time of
smoothness capability of the bicycle components is still observed.

[0009]The technical problem at the basis of the present invention is
therefore to ensure, in the assemblies of bicycle components in mutual
rotation, a high smoothness capability for an extended time period.

[0010]The present invention therefore relates, in a first aspect thereof,
to an assembly of bicycle components in mutual rotation, comprising a
support element, a rotary element rotatably coupled with the support
element, at least one bearing arranged between the support element and
the rotary element, said at least one bearing comprising a first bearing
element firmly coupled with one element from said support element and
said rotary element, characterised in that said first bearing element and
said one element from said support element and said rotary element have,
at respective mutually coupled interface surfaces, a standard reduction
potential difference lower than or equal to 0.3 V, in absolute value.

[0011]Throughout the present description and in the subsequent claims, the
expression "firmly coupled", is used to indicate a coupling without
relative motion between the two coupled elements.

[0012]Throughout the present description and in the subsequent claims, the
expression "bearing" is used to indicate any member intended to be
arranged between a first bicycle element and a second bicycle element to
allow the relative rotation of one element with respect to the other
element. Such a member can have the classic configuration of a rolling
bearing, with two rings and a plurality of rolling elements arranged
between the two rings, or a similar configuration, in which for example
one of the rings is omitted and the race for the rolling elements is
defined directly on one of the two bicycle elements in mutual rotation.

[0013]Throughout the present description and in the subsequent claims, the
expression "standard reduction potential value", is used to indicate the
value of the electrode potential referring to the standard hydrogen
electrode and measured at the following standard conditions: temperature
298 K, pressure 1 atm, concentration of the participants in the reaction
of 1 M.

SUMMARY

[0014]The Applicant has carefully studied the coupling between the two
bicycle components in mutual rotation at the coupling interface between
one of the two bicycle components and the bearing element fixedly coupled
with it and has surprisingly noted that such a coupling, which apparently
should not be responsible for smoothness capability since it is defined
between elements fixed to one another, i.e. without relative motion, in
reality has a direct influence upon such smoothness capability. The
Applicant has indeed found that the aforementioned coupling between
elements fixed to one another is subjected over time to phenomena of
corrosion that alter the coupling conditions between the two fixedly
coupled elements and, therefore, between the two bicycle components in
mutual rotation. In particular, the Applicant has found that the
aforementioned corrosion causes a movement of the bearing element with
respect to the bicycle element with which it is fixedly coupled,
consequently altering its interaction with the other elements of the
assembly. The Applicant has for example noted how the phenomena of
corrosion described above have a particularly negative effect in the case
of use of ball bearings, where perfect adjustment of the mounting
position of each element of the bearing and of the relative preloading is
required.

[0015]Moreover, the Applicant has noted how, even in the case in which a
protective system is used to prevent corrosion from directly attacking
the elements in mutual rotation, like grease and protective screens, the
corrosion at the coupling between firmly coupled elements propagates up
to the interface with the mobile elements directly responsible for
smoothness capability, so that smoothness capability in any case
decreases and, in the worst cases, becomes zero.

[0016]The Applicant has noted for example how, again in the case of use of
ball bearings, corrosion can occur at the interface between a ring of the
bearing and the bicycle element with which such a ring is firmly coupled
to then propagate inside the bearing until it reaches the ball races, in
this way altering the correct position of the balls.

[0017]The Applicant has observed in particular that the galvanic corrosion
is mainly liable for the occurrence of corrosion at the interface between
the firmly coupled elements of the assembly. This corrosion occurs due to
the effect of the action of atmospheric and/or polluting agents present
in the environment in which such an assembly operates.

[0018]Throughout the present description and in the subsequent claims,
"galvanic corrosion" is used to indicate the corrosion that occurs
between two surfaces in contact with one another situated in an
aggressive environment. In these circumstances, one of the two surfaces
behaves like a cathode and the other surface behaves like an anode.
Typically, the ion exchange between these surfaces causes that the anode
corrodes much faster than the cathode.

[0019]Advantageously, the Applicant has found that by selecting the
material of the aforementioned interface surfaces so as to have a
standard potential difference equal to or lower than the threshold of 0.3
V it is made more difficult for corrosion to occur at such interface
surfaces and its propagation inside the assembly is hindered, basically
achieving a satisfactory extension of the useful life of the assembly.

[0020]Preferably, the aforementioned standard reduction potential
difference is lower than or equal to 0.2 V, in absolute value, the
extremes being included.

[0022]Preferably, at least one from said first bearing element and said
one element from said support element and said rotary element has, at the
respective interface surface, a standard reduction potential comprised
between 0.16 and 0.18 V, the extremes being included. The Applicant has
noted that the extension of the useful life of the assembly is
particularly significant if the material of at least one of the
aforementioned interface surfaces is selected so as to have a standard
reduction potential within the aforementioned range of values.

[0023]In a preferred embodiment of the assembly of the present invention,
the interface surface of said first bearing element is made from
stainless steel. Preferably the aforementioned steel is of the
martensitic type, and more preferably it is X20Cr13.

[0024]Preferably, the interface surface of said one element from said
support element and said rotary element is made from a material selected
from: stainless steel, aluminum alloy treated with anodic oxidation,
metallic material coated with chemical nickel, composite material
comprising a filler incorporated in a matrix of polymeric material, such
a filler being coated with an insulating surface layer, for example
polymeric material the same as, or different to, that of the matrix.

[0027]Preferably, the polymeric material is a thermosetting material and
more preferably comprises an epoxy resin. However, the possibility of
using a thermoplastic material is not excluded.

[0028]In the preferred embodiment of the assembly of the present
invention, the aforementioned bearing also comprises a second bearing
element rotatably coupled with said first bearing element, said first
bearing element being firmly coupled with said rotary element and said
second bearing element being firmly coupled with said support element.

[0029]The second bearing element and said support element have respective
mutually coupled interface surfaces. Preferably, the material of the
interface surface of the second bearing element is identical to that of
the interface surface of the aforementioned first bearing element, but
the use of a different material is not excluded.

[0030]Preferably, therefore, the second bearing element and said support
element also have, at the respective interface surfaces, a standard
reduction potential difference lower than or equal to 0.3 V, in absolute
value, more preferably lower than or equal to 0.2 V, in absolute value,
the, extremes being included.

[0032]More preferably, at least one from said second bearing element and
said support element has, at the respective interface surface, a standard
reduction potential comprised between 0.16 and 0.18 V, the extremes being
included.

[0033]In the preferred embodiment of the assembly of the present
invention, the interface surface of said second bearing element is made
from stainless steel.

[0034]Preferably, the interface surface of said support element is made
from a material selected from: stainless steel, aluminum alloy treated
with anodic oxidation, metallic material coated with chemical nickel,
composite material comprising a filler incorporated in a matrix of
polymeric material, such a filler being coated with an insulating surface
layer, for example polymeric material the same as, or different to, that
of the matrix.

[0036]Preferably, the polymeric material also in this case is a
thermosetting material and more preferably comprises an epoxy resin.
However, the possibility of using a thermoplastic material is not
excluded.

[0037]In a particularly preferred embodiment of the assembly of the
present invention, said first and second bearing elements comprise
respective rings and said bearing comprises a plurality of rolling
elements arranged between said rings.

[0038]Preferably, said rolling elements are made from ceramic material.
Advantageously, the ceramic materials are electrically inert, for which
reason corrosion is prevented from starting inside the bearing.

[0039]More preferably, the ceramic material used has a density lower than
or equal to that of steel, even more preferably lower than or equal to 5
gr/cm3. In this way an advantageous reduction in weight is achieved
compared to conventional rolling elements made from steel.

[0040]Preferably, the rolling bearing with ceramic rolling elements has no
lubricants, so as to increase the smoothness capability compared to
conventional systems in which lubricants are used.

[0041]The Applicant has indeed observed that, in conventional systems in
which ball bearings are used on which grease is applied, part of the
desired smoothness capability is sacrificed, due to the viscous friction
generated by such grease. Moreover, the use of protective screens causes
a further reduction in the desired smoothness capability, due to the
sliding friction between such screens and the elements in rotation.
Advantageously therefore, the absence of lubricants in the assembly of
the present invention implies an increase in smoothness capability.
Moreover, with the assembly of the present invention it is no longer
necessary to carry out periodic maintenance of the rotary parts of the
assembly to refill or replace the amount of lubricant when it is
saturated with corrosive agents coming from the environment in which the
assembly operates. Such an advantage is particularly important given that
the maintenance interventions require experience not possessed by a large
number of cyclists.

[0042]The assembly of the present invention is preferably a bottom bracket
assembly, or a hub assembly, or a steering assembly of a bicycle.

[0043]In a second aspect thereof, the present invention relates to a
bicycle comprising at least one assembly of the type described above.

[0044]Preferably, such a bicycle has, individually or in combination, all
of the structural and functional characteristics discussed above with
reference to the assembly of the present invention and therefore it has
all of the aforementioned advantages.

BRIEF DESCRIPTION OF THE DRAWINGS

[0045]Further characteristics and advantages of the present invention
shall become clearer from some preferred embodiments thereof, made with
reference to the attached drawings and given for indicating and not
limiting purposes. In such drawings:

[0046]FIG. 1 is a longitudinal section view of a bottom bracket assembly
according to the present invention;

[0047]FIG. 2 is an enlarged view of a detail of the assembly of FIG. 1;

[0048]FIG. 3 is a longitudinal section view of a bicycle hub according to
the present invention; and

[0049]FIG. 4 is a longitudinal section view of a steering assembly
according to the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0050]With reference to FIG. 1 a first example of an assembly of bicycle
components provided with mutual rotary motion is illustrated. In
particular, it relates to a bottom bracket assembly, wholly indicated
with 1.

[0051]The assembly 1 comprises a shaft 5 supported in rotation in the
housing box 10 of a bicycle frame. The assembly 1 also comprises a pair
of adapters 15 screwed onto the opposite ends of the box 10 and a ball
bearing 20 arranged between each adapter 15 and the respective end of the
shaft 5.

[0052]In the example illustrated in FIG. 1, the adapters 15 acts as a
support element for the shaft 5, such a shaft being, on the other hand,
the rotary element of the assembly 1.

[0053]The man skilled in the art shall have no difficulty in understanding
that what will be stated hereafter is equally applicable to alternative
embodiments to the one illustrated in FIG. 1, in which for example
adapters 15 are not used and/or in which a type of bearings different to
the ball bearing 20 illustrated and described are used.

[0054]In the specific embodiment of the bottom bracket assembly 1
illustrated in FIG. 1, the shaft 5 is defined by two shaft elements 5a
and 5b connected to each other through a front toothing 6 of the Hirth
type and a locking screw 8. Each shaft element 5a , 5b is in turn
coupled, at the opposite end thereof to the one where the Hirth toothing
is provided, with a respective crank arm 25 through screwing.

[0055]Also in this case, the man skilled in the art will have no
difficulty in understanding that what shall be stated hereafter is
equally applicable to alternative embodiments to the one illustrated in
FIG. 1, in which for example the shaft 5 is in a single piece, or in
which one or both of the crank arms are made in one piece with a
respective shaft element, or in which the coupling of the crank arms with
the shaft or with the half-shaft takes place in a different way, for
example by interference or through grooved surfaces.

[0056]As better illustrated in FIG. 2, the element of the ball bearing 20
that is firmly coupled with the shaft 5 is the inner ring 30 of the
bearing. Such a coupling can be made with any known system, like a forced
coupling, and/or with abutment shoulders 32 formed on the shaft 5 and
stop elements 34 applied to the shaft 5 on the opposite side to the
shoulders 32 with respect to the bearings 20.

[0057]As better illustrated in FIG. 2, the inner ring 30 and the shaft 5
have respective interface surfaces 36 and 38 at which they are coupled
together.

[0058]The materials from which the interface surface 36 of the inner ring
30 of the bearing and the interface surface 38 of the shaft 5 are made
have a high resistance to corrosion, preferably to galvanic corrosion.

[0059]Preferably, the entire inner ring 30 is made from the same material
as the interface surface 36 thereof. Similarly, the entire shaft 5 is
made from the same material as the interface surface 38 thereof.

[0060]The standard reduction potential difference between the materials of
the interface surfaces 36 and 38 has an absolute value lower than or
equal to 0.3 V. It should be understood that the standard reduction
potential difference is the one between the materials in direct contact
with each other, for which reason if one of the two contact elements has
a surface oxidation or coating layer, it is necessary to consider the
standard reduction potential values of such a layer. The thickness of the
oxidation or coating layer is preferably comprised between 1 and 40
micron, the extremes being included.

[0061]Preferably, the materials of the interface surfaces 36 and 38 are
selected so that the respective standard reduction potential values fall
within the range between +0.4 V and -0.05 V, with an absolute value of
the standard reduction potential difference lower than or preferably
equal to 0.2 V. In particular, the interface surface 36 of the ring 30
preferably has a standard reduction potential value comprised between
0.16 and 0.18 V, the extremes being included, for which reason the
interface surface 38 of the shaft 5 preferably has a standard reduction
potential value of between -0.04 and +0.38 V, the extremes being
included.

[0062]Examples of materials for the interface surface 36 of the inner ring
30 and for the interface surface 38 of the shaft 5 are stainless steel
(preferably martensitic, preferably X20Cr13) for the interface surface 36
of the inner ring 30 and, for the interface surface 38 of the shaft 5,
one of the following materials:

[0063]stainless steel (preferably martensitic--preferably AISI 630);

[0064]aluminum alloys treated with anodic oxidation;

[0065]metallic material with a coating of chemical nickel;

[0066]composite material comprising a filler incorporated in a matrix of
polymeric material, in which the filler is coated with an insulating
surface layer, for example polymeric material the same as or different to
the matrix.

[0067]By composite material we mean a material comprising at least two
components including a polymeric matrix and a filler.

[0068]Preferably, the aforementioned composite material is a structural
composite material, but alternatively it can be a reinforced composite
material.

[0069]By structural composite materials we mean those materials that
contain structural fibres with a length of over five millimetres, whereas
by reinforced composite materials we mean those materials comprising a
polymeric matrix filled with fibres of a length lower than or equal to
five millimetres and/or with powders and/or granules. The sizes mentioned
above refer to the length of the fibre that can be found in a finished
piece.

[0070]Preferably, in the case in which in the assembly of the present
invention a composite material is used, such a material is a structural
composite material.

[0071]However, the use of a reinforced composite material is not excluded.

[0073]The arrangement of the structural fibres in the polymeric material
can be a random arrangement of pieces or sheets of structural fibres, a
substantially unidirectional ordered arrangement of fibres, a
substantially bidirectional ordered arrangement of fibres, or a
combination of the above.

[0074]The polymeric material is preferably thermosetting and preferably
comprises an epoxy resin. However, the possibility of using a
thermoplastic material is not excluded.

[0075]What has been stated above for the inner ring 30, the shaft 5 and
their mutual coupling is valid in a mirror-like way for the outer ring 40
of the bearing 20, the adapter 15 and their mutual coupling. In
particular, the outer ring 40 and the adapter 15 have respective
interface surfaces 42 and 44 made from materials having a high resistance
to corrosion, preferably to galvanic corrosion.

[0076]Preferably, such materials have an absolute value of the standard
reduction potential difference lower than or equal to 0.3 V, more
preferably lower than or equal to 0.2 V. In particular, the interface
surface 42 of the outer ring 40 preferably has a standard reduction
potential comprised between 0.16 and 0.18 V, the extremes being included.
Even more preferably, the interface surface 42 of the outer ring 40 is
made from the same material as the interface surface 36 of the inner ring
30, whereas the interface surface 44 of the adapter 15 is made from one
of the materials indicated above for the interface surface 38 of the
shaft 5.

[0077]Preferably, the entire outer ring 40 is made from the same material
as the interface surface 42 thereof. Similarly, the entire adapter 15 is
made from the same material as the interface surface 44 thereof.

[0078]The outer ring 40 is firmly coupled with the adapter 15 thanks to
the preloading exerted by the screw 8 (FIG. 1), through which it is
pushed into abutment against a shoulder 46 formed in the adapter 15.

[0079]The rings 30 and 40 each comprise a rolling race 48a and 48b for a
number of balls 50.

[0080]The balls are preferably made from ceramic material. Examples of
suitable ceramic materials are silicon nitride and alumina. Preferably,
such a ceramic material has a density lower than or equal to that of
steel, more preferably lower than or equal to 5 gr/cm3.

[0081]FIG. 3 illustrates a second example of an assembly of bicycle
components equipped with mutual rotary motion, in accordance with the
present invention. In particular, it relates to a hub assembly, wholly
indicated with 201.

[0082]The assembly 201 comprises a shaft 205, an outer shell 215 and
bearings 220. The shaft 205, which is intended to remain fixed with
respect to the frame of a bicycle, in this case acts as a support
element, whereas the shell 215, intended to rotate with respect to the
shaft 205, acts as an element supported in rotation through the
interposition of the bearings 220.

[0083]Although the arrangement of the support element 205 and of the
rotary element 215 are inverted here with respect to the bottom bracket
assembly 1 described above, the couplings of the rings 230 and 240 with
these elements have the same characteristics as those described above.

[0084]FIG. 4 illustrates a third example of an assembly of bicycle
components equipped with mutual rotary motion, in accordance with the
present invention. In particular it relates to a steering assembly,
wholly indicated with 301.

[0085]The assembly 301 comprises a steering tube 305 rotatably coupled
with a steering column 315 of the frame of a bicycle through the
interposition of a pair of bearings 320 provided with rings 330, 340. In
this case the support element is the column 315, whereas the rotary
element is the steering tube 305. The coupling between the bearings 320
and the column 315 is a direct contact coupling, for which reason it
preferably has the properties of standard reduction potential difference
described above.

[0086]Just ball bearings have been described above. However, any type of
bearing can be used, like for example a bearing with different shaped
rolling elements, like rollers, or more generally members shaped in a
similar way to rolling bearings.

[0087]Preferably, when the bearing is provided with rolling elements, with
rings made from stainless steel and rolling elements made from ceramic
material, no lubricant in used in the bearing.

[0088]Of course, a man skilled in the art can bring numerous modifications
to the assembly described above, in order to satisfy specific and
contingent requirements, all of which are in any case within the scope of
protection of the present invention as defined by the following claims.